1. R epresentation O f S timuli A s N eural A ctivity ROSANA Project UCM-UAM-FrI-UPo-UEs

2. “ Perception ” ⇩ “ Internal Representation ” of the external world we will be able to reproduce the same spatiotemporal pattern of activity Understand the fundaments of perception Determine the principles of coding of sensory stimuli Interactions sensory inputs - activity of CNS neurons

3. Lemniscal somatosensory system 10.000 500.000

4. Our Experiment

5. State of the project (started May 2002) We set-up a complete electrophysiology lab We implanted sieve microelectrodes in the peripheral nerve of rats and cats We obtained functional regeneration of the sensory nerves We recorded the electrical activity of the regenerated nerves We recorded electrical activity simultaneously from the regenerated nerve and from neurons in the CNS We developed mathematical and computational models of oscillating neurons We deveoped specific microstimulators to control the stimulation We are developing new microstimulators to control the stimulation We are developing new mathematical and computational models We are developing new microelectrodes We are setting-up the 140 simultaneous recording procedure We are setting-up the new data analysis techniques

6. Gr Cu PROJECTION NEURONS DENDRITES Glomeruli C R D V

7. Azar s 0 10 20 30 Amplitud (mV) -70 -50 -30 -60-60 -64 -68 Amplitud (mV) 2 s -80-80 -40-40 4040 0 Amplitud (mV) 020 40 s 6,0 Hz 0100002000030000 -70 -50 -30 7,5 HZ -70 -50 -30

8. Problems to be solved 1.If artificial sensors are to be directly connected to the nerve(s), only a very low number of fibers can be interfaced 2.Interfacing of artificial sensors to a sensory nerve will submit to each axon information concerning different sensory submodalities in an entirely unpredictable fashion